delphi 里的二分法查找

procedure TForm1.Button3Click(Sender: TObject);
var
  a :array[0..100] of Integer;
  chazhao :Integer;
  l,h,m :Integer;
  found :Boolean;

begin
  chazhao :=StrToInt(Edit1.Text);
  for i :=0 to 100 do
  begin
    a[i] :=i;
  end;


  l :=Low(a);
  h :=High(a);


  while l<=h do
  begin
    m := (l + h) div 2;
    if chazhao < a[m] then
    begin
      h :=m -1;
      found :=False;
    end else if chazhao > a[m] then
    begin
      l :=m+1 ;
      found :=False;
    end else if chazhao =a[m]  then
    begin
      ShowMessage('found number !');
      found :=True;
      Break;
    end;
    Application.ProcessMessages;
  end;
  if not found then  ShowMessage('not found number !');
end;